The disclosure provides a projection device and a parameter adjustment method thereof. An environment detection value is received from a detection module through a control chip, wherein the environment detection value is at least one of an environment illuminance value, a volume load value and an environment volume value. Then, the environment detection value is compared with a reference range to obtain a corresponding environment mode. Furthermore, a rotation speed of a fan module is adjusted according to an environment load value corresponding to the environment mode. The projection device and the parameter adjustment method thereof provided by the invention make the illuminance and noise output of the projection device more suitable for the operation condition.